I recently acquired a couple of hp 41CV's and one came with a
rechargeable battery pack. when I tried to recharge the battery pack
it didn't seem to be very cooperative and I decided to use a power
supply to give it a little push. And so the little push became a bit
bigger and bigger until my battery pack got short-circuited.
When I opened the damn thing I noticed that I got more than I expected.
And yes I fried the zener diode across the battery terminals, it was
well-done because it left it's mark on the pcb.
Could someone with a hp 41CV calculator measure the voltage across the
battery terminals with a fully charged pack and the charger connected.
The zener voltage could be 6V2 or 6V8, but it's also possible that they
used a custom zener. Most parts in the circuit had meaningless numbers
except for the voltage regulator, the two capacitors and the resistor.
I hope I'm not the only one who can't handle a "normal" calculator.
on1aag.
rechargeable battery pack. when I tried to recharge the battery pack
it didn't seem to be very cooperative and I decided to use a power
supply to give it a little push. And so the little push became a bit
bigger and bigger until my battery pack got short-circuited.
When I opened the damn thing I noticed that I got more than I expected.
And yes I fried the zener diode across the battery terminals, it was
well-done because it left it's mark on the pcb.
Could someone with a hp 41CV calculator measure the voltage across the
battery terminals with a fully charged pack and the charger connected.
The zener voltage could be 6V2 or 6V8, but it's also possible that they
used a custom zener. Most parts in the circuit had meaningless numbers
except for the voltage regulator, the two capacitors and the resistor.
I hope I'm not the only one who can't handle a "normal" calculator.
on1aag.